def a ;
println a?.toUpperCase()
//Elvis


def res ;
res = 'jack'
println res?:"unknown";

def today = Day.MONDAY
switch (today) {
    //Saturday or Sunday
    case [Day.SATURDAY, Day.SUNDAY]:
    println "Weekends are cool"
    break
    //a day between Monday and Friday
    case Day.MONDAY..Day.FRIDAY:
    println "Boring work day"
    break
    default:
    println "Are you sure this is a valid day?"
}
enum Day {
    SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
    THURSDAY, FRIDAY, SATURDAY
}
             

